you can do it yourself with a product called gunkote available from me or brownells.
I use it all the time on stainless parts for the guns I work on and occasionaly whole guns. I sandblast the surface myself but as long as you can scuff it up and get it perfectly clean before spraying you will be fine. It also must be baked at 300 deg for an hour to cure. Once done, it ain't coming off from solvents or regular use. Brownells has a variety of colors available and they really are easy to do at home. I'm in the process of moving to a farm outside of town right now or I'd offer to do it for you but take a look at these few pics of things I've done in black and OD green. (the matte black usually comes out much flatter. I just found out I got a mislabeled can from them and they are sending me a new one as we speak. )
Here's a link to pics. http://www.dansshootingsupply.com/gun%20refinishing.htm